/**************************************************************************/
/*  transform_2d.h                                                        */
/**************************************************************************/
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/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
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#pragma once
#include "backend/text_server/rect2.h"
#include "backend/text_server/vector2.h"
#include "backend/text_server/godot_containers.hpp"
#include <cmath>

namespace godot
{
class String;

struct Transform2D {
    // Warning #1: basis of Transform2D is stored differently from Basis. In terms of columns array, the basis matrix looks like "on paper":
    // M = (columns[0].x columns[1].x)
    //     (columns[0].y columns[1].y)
    // This is such that the columns, which can be interpreted as basis vectors of the coordinate system "painted" on the object, can be accessed as columns[i].
    // Note that this is the opposite of the indices in mathematical texts, meaning: $M_{12}$ in a math book corresponds to columns[1].x here.
    // This requires additional care when working with explicit indices.
    // See https://en.wikipedia.org/wiki/Row-_and_column-major_order for further reading.

    // Warning #2: 2D be aware that unlike 3D code, 2D code uses a left-handed coordinate system: Y-axis points down,
    // and angle is measure from +X to +Y in a clockwise-fashion.

    Vector2 columns[3];

    _FORCE_INLINE_ real_t tdotx(const Vector2& v) const { return columns[0].x * v.x + columns[1].x * v.y; }
    _FORCE_INLINE_ real_t tdoty(const Vector2& v) const { return columns[0].y * v.x + columns[1].y * v.y; }

    const Vector2& operator[](int p_idx) const { return columns[p_idx]; }
    Vector2&       operator[](int p_idx) { return columns[p_idx]; }

    void        invert();
    Transform2D inverse() const;

    void        affine_invert();
    Transform2D affine_inverse() const;

    void                set_rotation(const real_t p_rot);
    real_t              get_rotation() const;
    real_t              get_skew() const;
    void                set_skew(const real_t p_angle);
    _FORCE_INLINE_ void set_rotation_and_scale(const real_t p_rot, const Size2& p_scale);
    _FORCE_INLINE_ void set_rotation_scale_and_skew(const real_t p_rot, const Size2& p_scale, const real_t p_skew);
    void                rotate(const real_t p_angle);

    void scale(const Size2& p_scale);
    void scale_basis(const Size2& p_scale);
    void translate_local(const real_t p_tx, const real_t p_ty);
    void translate_local(const Vector2& p_translation);

    real_t basis_determinant() const;

    Size2 get_scale() const;
    void  set_scale(const Size2& p_scale);

    _FORCE_INLINE_ const Vector2& get_origin() const { return columns[2]; }
    _FORCE_INLINE_ void           set_origin(const Vector2& p_origin) { columns[2] = p_origin; }

    Transform2D scaled(const Size2& p_scale) const;
    Transform2D scaled_local(const Size2& p_scale) const;
    Transform2D translated(const Vector2& p_offset) const;
    Transform2D translated_local(const Vector2& p_offset) const;
    Transform2D rotated(const real_t p_angle) const;
    Transform2D rotated_local(const real_t p_angle) const;

    Transform2D untranslated() const;

    void        orthonormalize();
    Transform2D orthonormalized() const;

    // bool is_equal_approx(const Transform2D &p_transform) const;
    // bool is_finite() const;
    // Transform2D looking_at(const Vector2 &p_target) const;

    bool operator==(const Transform2D& p_transform) const;
    bool operator!=(const Transform2D& p_transform) const;

    void        operator*=(const Transform2D& p_transform);
    Transform2D operator*(const Transform2D& p_transform) const;
    void        operator*=(const real_t p_val);
    Transform2D operator*(const real_t p_val) const;

    // Transform2D interpolate_with(const Transform2D &p_transform, const real_t p_c) const;

    _FORCE_INLINE_ Vector2 basis_xform(const Vector2& p_vec) const;
    _FORCE_INLINE_ Vector2 basis_xform_inv(const Vector2& p_vec) const;
    _FORCE_INLINE_ Vector2 xform(const Vector2& p_vec) const;
    _FORCE_INLINE_ Vector2 xform_inv(const Vector2& p_vec) const;
    _FORCE_INLINE_ Rect2   xform(const Rect2& p_rect) const;
    _FORCE_INLINE_ Rect2   xform_inv(const Rect2& p_rect) const;
    _FORCE_INLINE_ Vector<Vector2> xform(const Vector<Vector2>& p_array) const;
    _FORCE_INLINE_ Vector<Vector2> xform_inv(const Vector<Vector2>& p_array) const;

    // operator String() const;

    Transform2D(const real_t xx, const real_t xy, const real_t yx, const real_t yy, const real_t ox, const real_t oy)
    {
        columns[0].x = xx;
        columns[0].y = xy;
        columns[1].x = yx;
        columns[1].y = yy;
        columns[2].x = ox;
        columns[2].y = oy;
    }

    Transform2D(const Vector2& p_x, const Vector2& p_y, const Vector2& p_origin)
    {
        columns[0] = p_x;
        columns[1] = p_y;
        columns[2] = p_origin;
    }

    Transform2D(const real_t p_rot, const Vector2& p_pos);

    Transform2D(const real_t p_rot, const Size2& p_scale, const real_t p_skew, const Vector2& p_pos);

    Transform2D()
    {
        columns[0].x = 1.0;
        columns[1].y = 1.0;
    }
};

Vector2 Transform2D::basis_xform(const Vector2& p_vec) const
{
    return Vector2(
    tdotx(p_vec),
    tdoty(p_vec));
}

Vector2 Transform2D::basis_xform_inv(const Vector2& p_vec) const
{
    return Vector2(
    columns[0].dot(p_vec),
    columns[1].dot(p_vec));
}

Vector2 Transform2D::xform(const Vector2& p_vec) const
{
    return Vector2(
           tdotx(p_vec),
           tdoty(p_vec)) +
           columns[2];
}

Vector2 Transform2D::xform_inv(const Vector2& p_vec) const
{
    Vector2 v = p_vec - columns[2];

    return Vector2(
    columns[0].dot(v),
    columns[1].dot(v));
}

Rect2 Transform2D::xform(const Rect2& p_rect) const
{
    Vector2 x = columns[0] * p_rect.size.x;
    Vector2 y = columns[1] * p_rect.size.y;
    Vector2 pos = xform(p_rect.position);

    Rect2 new_rect;
    new_rect.position = pos;
    new_rect.expand_to(pos + x);
    new_rect.expand_to(pos + y);
    new_rect.expand_to(pos + x + y);
    return new_rect;
}

void Transform2D::set_rotation_and_scale(const real_t p_rot, const Size2& p_scale)
{
    columns[0].x = ::cos(p_rot) * p_scale.x;
    columns[1].y = ::cos(p_rot) * p_scale.y;
    columns[1].x = -::sin(p_rot) * p_scale.y;
    columns[0].y = ::sin(p_rot) * p_scale.x;
}

void Transform2D::set_rotation_scale_and_skew(const real_t p_rot, const Size2& p_scale, const real_t p_skew)
{
    columns[0].x = ::cos(p_rot) * p_scale.x;
    columns[1].y = ::cos(p_rot + p_skew) * p_scale.y;
    columns[1].x = -::sin(p_rot + p_skew) * p_scale.y;
    columns[0].y = ::sin(p_rot) * p_scale.x;
}

Rect2 Transform2D::xform_inv(const Rect2& p_rect) const
{
    Vector2 ends[4] = {
        xform_inv(p_rect.position),
        xform_inv(Vector2(p_rect.position.x, p_rect.position.y + p_rect.size.y)),
        xform_inv(Vector2(p_rect.position.x + p_rect.size.x, p_rect.position.y + p_rect.size.y)),
        xform_inv(Vector2(p_rect.position.x + p_rect.size.x, p_rect.position.y))
    };

    Rect2 new_rect;
    new_rect.position = ends[0];
    new_rect.expand_to(ends[1]);
    new_rect.expand_to(ends[2]);
    new_rect.expand_to(ends[3]);

    return new_rect;
}

Vector<Vector2> Transform2D::xform(const Vector<Vector2>& p_array) const
{
    Vector<Vector2> array;
    array.resize_default(p_array.size());

    const Vector2* r = p_array.ptr();
    Vector2*       w = array.ptrw();

    for (int i = 0; i < p_array.size(); ++i)
    {
        w[i] = xform(r[i]);
    }
    return array;
}

Vector<Vector2> Transform2D::xform_inv(const Vector<Vector2>& p_array) const
{
    Vector<Vector2> array;
    array.resize_default(p_array.size());

    const Vector2* r = p_array.ptr();
    Vector2*       w = array.ptrw();

    for (int i = 0; i < p_array.size(); ++i)
    {
        w[i] = xform_inv(r[i]);
    }
    return array;
}

} // namespace godot